„… objectively the opportunists are a section of the petty bourgeoisie and of a certain strata of the working class who have been bribed out of imperialist superprofits and converted to watchdogs of capitalism and corruptors of the labour movement.“ (W. I. Lenin: Imperialism and the Split in Socialism (1916) (emphasis in the original))

“Obviously, out of such enormous superprofits (since they are obtained over and above the profits which capitalists squeeze out of the workers of their "own" country) it is possible to bribe the labour leaders and the upper stratum of the labour aristocracy. And that is just what the capitalists of the "advanced" countries are doing: they are bribing them in a thousand different ways, direct and indirect, overt and covert. This stratum of workers-turned-bourgeois, or the labour aristocracy, who are quite philistine in their mode of life, in the size of their earnings and in their entire outlook, is the principal prop of the Second International, and in our days, the principal social (not military) prop of the bourgeoisie. For they are the real agents of the bourgeoisie in the working-class movement, the labour lieutenants of the capitalist class, real vehicles of reformism and chauvinism. In the civil war between the proletariat and the bourgeoisie they inevitably, and in no small numbers, take the side of the bourgeoisie, the "Versaillese" against the "Communards". Unless the economic roots of this phenomenon are understood and its political and social significance is appreciated, not a step can be taken toward the solution of the practical problem of the communist movement and of the impending social revolution.” (W. I. Lenin: Imperialism, The Highest Stage of Capitalism (1916) (emphasis in the original))

„Firstly, chauvinism and opportunism in the labour movement have the same economic basis: the alliance between a numerically small upper stratum of the proletariat and the petty bourgeoisie—who get but morsels of the privileges of their “own” national capital—against the masses of the proletarians, the masses of the toilers and the oppressed in general.“ (W. I. Lenin: The Collapse of the Second International (1915)

„Neither we nor anyone else can calculate precisely what portion of the proletariat is following and will follow the social-chauvinists and opportunists. This will be revealed only by the struggle, it will be definitely decided 9 only by the socialist revolution. But we know for certain that the “defenders of the fatherland” in the imperialist war represent only a minority. And it is therefore our duty, if we wish to remain socialists to go down lower and deeper, to the real masses; this is the whole meaning and the whole purport of the struggle against opportunism. By exposing the fact that the opportunists and social-chauvinists are in reality betraying and selling the interests of the masses, that they are defending the temporary privileges of a minority of the workers, that they are the vehicles of bourgeois ideas and influences, that they are really allies and agents of the bourgeoisie, we teach the masses to appreciate their true political interests, to fight for socialism and for the revolution through all the long and painful vicissitudes of imperialist wars and imperialist armistices. The only Marxist line in the world labour movement is to explain to the masses the inevitability and necessity of breaking with opportunism, to educate them for revolution by waging a relentless struggle against opportunism, to utilise the experience of the war to expose, not conceal, the utter vileness of national-liberal labour politics.“ (W. I. Lenin: Imperialism and the Split in Socialism (1916) (emphasis in the original))

_________________"The world political situation as a whole is chiefly characterized by a historical crisis of the leadership of the proletariat."--Trotsky, Transitional Program (1938)

“Anti-capitalism doesn’t do the victims of capitalism any good if you don’t actually destroy capitalism.”(‘The Historical Failure of Anarchism)